The present invention is characterized as a fluid flow valve and is particularly useful in the field of vacuum pressure components used with generated vacuum pressure in pick and place applications.
Vacuum valves are useful for manipulating a work piece in pick and place applications. An external pressure source is applied to the valve which typically has a suction head attached, the suction head is contacted to the work piece, which is then lifted depending on the porting of vacuum pressure through the valve. Alternate valve designs have evolved to increase the efficiency of the use of vacuum pressure. Two designs include dual flow and tri-flow type valve designs.
Dual flow valves are generally limited to a small fluid flow through an orifice and are preferred in applications when suction heads many not be in sealing contact with the work piece. Because of the small fluid flow rate, dual flow valves will limit vacuum pressure loss to the orifice flow when sealing contact is not met with the work piece. However, the small fluid flow rate limits dual flow valves to applications involving non-porous work pieces.
Try-flow valves are not limited to a small fluid flow orifice flow rate and therefore offer greater utility at the expense of greater complexity. Tri-flow valves generally have a full-open vacuum state that permits the application of the full vacuum potential applied to a valve. Moreover, the inclusion of a flow sensor enables the tri-flow valve to determine when a suction head has not made sealing contact with the work piece and decrease the leakage of the tri-flow valve to the orifice flow rate.
With either of the above discussed dual-flow or tri-flow valve, there is always an inherent leakage if a non-sealing contact is made with the work piece. It would be desirable to eliminate or minimize the orifice flow rate leakage in pick and place applications to conserve vacuum pressure and the energy required to create vacuum pressure. This inherent undesirable characteristic of the above valve designs is further aggravated when an array of dual-flow and/or tri-flow valves are working in parallel off the same vacuum generator.
A further undesirable characteristic of the above valves designs is the necessity to have visual confirmation of contact of the suction head to the work piece prior to turning on the vacuum pressure. In other words, vacuum pressure is ordinarily not applied in a system including the above valve types until there is contact between the suction head and the work piece. It would instead be desirable to enable the valve with the functionality to determine the proper instant to apply vacuum pressure. Such functionality would further enable the saving of vacuum pressure in a pick and place application.
The present invention is characterized as a two way valve within a housing 20 that has a valve chamber bounded by a valve chamber wall 24 and having a first valve chamber opening bounded by a first valve chamber opening edge 26 and a fluid flow opening bounded by a fluid flow opening edge 27. A chamber shuttle 30, characterized by a chamber shuttle cavity bounded by a chamber shuttle cavity wall 31 and having a first chamber shuttle cavity opening bounded by a first chamber shuttle cavity opening edge 33 and a second the chamber shuttle 30 adapted to travel within the valve chamber, and a second chamber shuttle cavity opening bounded by a second chamber shuttle cavity opening edge 35. A shuttle-plug 40 that is biased by a force 50 against the first chamber shuttle cavity opening edge 33 to establish a closed fluid-flow state, the chamber shuttle 30 movable against the biasing force 50 thereby resisting the shuttle-plug 40 by a structure fixed relative to the valve chamber and opening the chamber shuttle cavity to establish a second fluid-flow state. A preferred embodiment of the invention is incorporated in a valve construction of components that incorporate aspects of the invention described above.
A first objective of the invention is to provide a two way valve with very small leakage and full blow-off capability.
A second objective of the invention is to provide a economically feasible valve construction incorporating aspects of the invention.